Pre pressing of Hanyi ball spline

1. The function of preloading
Eliminating clearance: It can make the clearance in the direction of rotation of the ball spline zero, reduce the free movement of the ball in the raceway, and thus improve the positioning accuracy and repeat positioning accuracy.
Improving rigidity: It can significantly enhance the rigidity of ball splines, making them deform less when subjected to loads, thereby improving transmission accuracy. Compared with no preloading, the displacement can be significantly reduced and the rigidity can be increased by more than twice when the same torque is applied.
Extended service life: Proper preloading can evenly distribute the force on the ball, reduce local stress concentration, and thus extend the service life of the ball spline.
2. Pre compression level and application scenarios
Zero preload P0: Suitable for places where small forces are needed to drive smoothly, and where torque always acts in a certain direction, such as various measuring instruments, automatic gun roundness machines, power meters, winding machines, automatic welding machines, automatic packaging machines, shape measuring devices, etc.
Light preloading P1: Used for places that bear cantilever loads or torque, require high precision repetition, and have alternating loads, such as rocker arms of industrial robots, various automatic loading and unloading machinery, automatic coating guide shafts, EDM machine spindles, stamping punch guide shafts, drilling machine spindles, etc.
Medium preloading P2: commonly used in places that require high rigidity and are prone to vibration and impact, where one spline outer cylinder is subjected to torque, such as the steering control shaft, welding shaft, automatic disc tool table indexing shaft, etc. of construction vehicles.
3. Implementation method of preloading
Adopting angular contact structure: For example, the Hanyi ball spline uses two opposite steel ball rows with a contact angle of 20 ° to clamp the protruding part of the Hanyi spline shaft and apply pre pressure angular contact structure, so that the clearance in the rotation direction can be zero, thereby improving rigidity.
Using a preloading device or adjusting nut: For ball screws, an adjusting nut is usually installed at the rear bearing, and the torque of the adjusting nut is gradually adjusted using a torque wrench or torque wrench until the expected preloading value is reached.
4. Precautions for preloading adjustment
Determination of Pre pressure Size: Pre pressure needs to be reasonably estimated and adjusted during design based on the usage conditions and requirements of the ball spline. If it is too small, it will lead to excessive clearance and reduced accuracy, while if it is too large, it will increase the resistance and shorten the service life of the ball spline.
Pressure control during installation: During the pressure application process, the pressure should be slowly increased to avoid applying excessive pressure instantly. The pressure can be gradually increased from 0 to the set value, and real-time monitoring of pressure changes through pressure sensors and other means can be used to control pressure fluctuations within a small range.
Inspection and verification after installation: After installation, it is necessary to check the preloading effect of the ball spline, such as checking the rotational flexibility of the spline, measuring the gap size, conducting load testing, etc., to ensure that the preloading achieves the expected effect and the spline works normally.